1. Field of the Invention
The invention relates to a semiconductor device, and more particularly, to a blank mask and a manufacturing method thereof.
2. Brief Description of Related Technology
A mask is used during a process of transferring patterns for a semiconductor device onto a wafer. A mask is manufactured by forming mask patterns having a layout of patterns to be transferred to a transparent substrate. Such a mask is manufactured by performing a patterning process for mask patterns on a blank mask including a layer for the mask patterns formed on the transparent substrate. The blank mask may be maintained in a state where any defect is not substantially generated before patterning of a mask layer is performed.
When packed or otherwise stored prior to use, it is frequently the case that foreign substances accumulate and are absorbed onto the surface of the blank mask, thereby generating defects during a subsequent process. To suppress this defect generation, a pre-inspection and washing to remove foreign substances upon detection of the foreign substances are performed before a patterning process is performed on the blank mask. However, the inspection and washing processes increase process time, which lowers productivity of the entire mask manufacturing process. Also, when defects are generated during the inspection process after mask manufacturing, a valuable mask is lost. Therefore, it is very important to remove foreign substances or particles from an initial blank mask.